UNIVERSITY     OF     CALIFORNIA  AGRICULTURAL  EXPERIMENT  STATION 

COLLEGE    OF    AGRICULTURE  BENJ-  IDE  wheeler,  president 

THOMAS    FORSYTH    HUNT,    DEAN    and    DIRECTOR 
BERKELEY  H,    E.   VAN    NORMAN,   Vice-Director   and    Dean 

University  Farm    School 


CIRCULAR  No.  180. 
October,  1917. 

SELECTING  CORN  SEED. 

By  Ernest  B.   Babcock. 

The  growing  of  Indian  corn  in  California  is  increasing.  In  1915 
there  were  64,000  acres  in  corn  and  there  is  probably  double  that 
acreage  in  1917.  This  is  fortunate  in  view  of  the  present  emergency, 
for  it  is  desirable  that  corn  production  be  increased  in  order  to  stop 
the  importation  of  corn  from  Eastern  states.  There  is  sufficient  suitable 
land  in  the  favorable  districts  for  corn  growing  to  allow  still  further 
increase  in  acreage,  and  certain  varieties  can  be  grown  successfully  in 
districts  where  very  little  corn  is  now  grown.  Corn  is  also  a  splendid 
crop  to  use  in  rotation  with  potatoes  for  the  purpose  of  eradicating 
disease-causing  organisms  that  live  in  the  soil.  But,  while  extension 
of  the  corn  acreage  would  result  in  greater  production,  it  would  not 
tend  to  improve  the  quality  of  the  corn  produced  in  this  state.  It  is 
important,  however,  that  the  milling  quality  of  our  corn  be  greatly 
improved. 

The  quality  of  the  corn  crop  is  determined  by  two  general  factors, 
viz.,  (1)  by  methods  of  culture  and  of  handling  the  crop;  (2)  by  the 
kind  of  seed  used.  Cultural  methods  will  not  be  discussed  in  this 
circular  but  the  handling  of  newly  harvested  corn  may  be  considered. 
Mature  corn  contains  from  20  to  30  per  cent  of  moisture  and  if  it  is 
stored  without  being  thoroughly  dried  it  is  certain  to  mold  and  thus 
to  be  seriously  damaged.  Thorough  drying  means  reduction  of  the 
moisture  content  to  13  or  14  per  cent.  Many  farmers  do  not  wait  until 
the  corn  has  dried  sufficiently  before  shelling  but  attempt  to  market 
the  crop  while  the  moisture  content  is  from  17  to  22  per  cent.  This  is 
almost  certain  to  result  in  deterioration  of  the  corn.  Therefore  the 
newly  harvested  corn  should  not  be  shelled  until  after  the  ears  are  no 
longer  limber,  but  firm  so  they  snap  when  broken,  and  the  chaff  that 
comes  off  when  shelling  is  dry  and  easily  blowTn  out.  For  those  who 
grow  corn  extensively  it  is  practicable  and  inexpensive  to  test  the 
moisture  content  of  the  drying  corn  from  time  to  time.  (For  infor- 
mation regarding  methods  and  necessary  equipment  apply  to  The  Dean, 
College  of  Agriculture,  Berkeley.)  Shelled  corn  should  be  thoroughly 
cleaned  because  chaff  and  pieces  of  cob  hold  moisture  and  increase  the 
danger  of  deterioration. 

33912 


But  even  when  properly  handled  California  corn  is  generally  of 
poorer  grade  than  it  should  be  and  would  be  if  seed  selection  were 
commonly  practiced.  By  proper  care  in  seed  selection  and  planting 
it  is  possible  not  only  to  attain  any  desired  degree  of  uniformity  but 
even  the  chemical  composition  of  the  corn  kernel  itself  can  be  modified 
as  desired.  This  responsiveness  of  corn  to  the  influence  of  selection 
has  been  known  and  utilized  for  years  in  the  corn  belt  states  and  in  a 
few  instances  in  this  state,  but  California  corn  growers  in  general 
have  derived  very  little  benefit  from  seed  selection.  Corn  is  very 
susceptible  to  a  change  of  climate  or  soil,  so  that  it  is  always  necessary 
to  acclimate  a  variety  new  to  California  and  then  by  seed  selection  to 
save  and  multiply  those  strains  that  produce  the  highest  yield  and  best 
quality.  Yet  many  California  growers  have  been  using  seed  imported 
each  year  from  the  middle  west  or  else  have  planted  unselected  seed 
from  varieties  which  have  become  acclimated,  such  as  the  King  Phillip 
variety.  "While  the  average  yield  per  acre  in  California  compares 
favorably  with  the  average  yield  in  the  corn  belt  states,  it  must  be 
remembered  that  most  of  our  corn  is  grown  on  deep  soils  and  under 
irrigation.  With  proper  seed  selection,  therefore,  the  average  yield  per 
acre  in  California  should  exceed  the  average  yield  in  humid  climates, 
while  the  uniformity  of  our  product  should  come  to  equal  that  of  older 
corn  growing  regions. 


Fig.   1. 


Lowell  Trubody,  of  Napa  High  School  Agriculture  Club,  who  has  produced  over 
100  bushels  per  acre  for  four  successive  years. 


—  3  — 

That  seed  selection  is  just  as  effective  in  California  as  it  is  elsewhere 
has  been  shown  by  the  boys'  corn  clubs  of  this  state.  The  experience 
of  the  Napa  County  clubs  exemplifies  this  fact  especially  well.  In 
1913  Lowell  Trubocly  of  the  Napa  High  School  Agriculture  Club 
secured  seed  corn  of  the  Reid  Yellow  Dent  variety  from  a  neighbor  who 
had  practiced  seed  selection  for  two  years.  This  boy  has  continued  to 
select  his  seed  and  has  produced  over  100  bushels  on  his  acre  of  ground 
each  year.  As  shown  in  Fig.  1  there  is  still  need  of  selection  for 
position  of  ear  on  the  plant.  Several  other  contestants  have  secured 
their  seed  from  Trubody  with  notably  successful  results.  What  can 
be  accomplished  by  high  school  boys  can  be  done  by  every  farmer  who 
is  willing  to  make  the  effort.  Corn  growers  have  a  patriotic  duty  to 
perform  which  is  likely  to  increase  their  production  from  10  to  25  per 
cent  and  to  improve  the  quality  of  their  crop  by  making  it  more 
uniform. 

Field  Selection, 

The  following  directions  are  adapted  to  the  needs  of  individual 
growers  who  wish  to  increase  their  corn  crop.  But  they  will  also 
serve  to  guide  local  community  efforts  to  secure  better  seed  corn  for  the 
1918  crop.  In  the  present  emergency,  with  increasing  use  of  corn 
products,  such  efforts  should  go  as  far  as  possible.  The  best  fields 
should  be  located  and,  if  possible,  the  seed  ears  should  be  gathered  by 
a  special  crew  of  pickers.  Each  man  or  boy  should  be  furnished  with 
a  picking  sack  which  can  be  slung  over  the  shoulder..  When  filled  the 
sacks  may  be  dumped  into  a  near-by  wagon.  If  sacks  are  not  avail- 
able the  wagon  can  move  up  and  down  the  field  with  the  pickers  by 
topping  an  occasional  row. 

Time  to  Select  Seed  Corn.  The  best  time  to  select  seed  corn  is 
just  at  maturity  and  from  the  standing  corn.  If  the  seed  is  selected 
from  the  crib,  or  after  husking,  only  the  size  and  shape  of  the  ears  can 
be  considered;  there  is  then  no  way  to  tell  whether  the  fine  looking 
ears  were  grown  on  excellent  plants  or  not,  or  whether  the  best  ears 
in  the  crib  owe  their  superiority  to  heredity  or  to  better  soil  and 
moisture  conditions. 

Kind  of  Plant  to  Select.  An  excellent  corn  plant  is  one  that  pro- 
duces a  large  yield  of  fine  grain  when  grown  in  normal  competition 
with  other  plants.  When  working  with  dent  corns  select  plants  having 
one  or  two  good  ears  to  the  stalk.  Flint  corns,  like  King  Phillip,  tend 
to  produce  more  ears  and  can  be  selected  for  three  or  four  ears  per 
stalk.  Pick  plants  that  mature  at  nearly  the  same  time;  this  will 
make  for  uniformity  in  ripening.  Plants  should  be  of  medium  size 
rather  than  very  tall  or  short;  they  should  also  be  strong  and  well 


—  4  — 

rooted,  able  to  withstand  heavy  winds.  The  distance  between  the 
joints  should  be  short.  The  position  of  the  ears  should  be  about  four 
feet  from  the  ground.  Seed  should  not  be  taken  from  plants  showing 
smut  or  other  diseases  or  from  plants  standing  near  smutty  plants. 


Fig.  2.  'Corn  grown  by  Alvin  Hurd  of  the  St.  Helena  High  School  Agricultural  Club. 
This  boy  produced  more  than  double  the  yield  of  his  neighbor.  He  used  selected 
seed  grown  by  Lowell  Trubody. 

Kind  of  Ears  to  Select.  The  ideal  ear  is  cylindrical  or  tapering  only 
slightly  from  butt  to  tip,  with  butts  and  tips  well  filled  out  and  with 
the  husks  long  and  tightly  folded  about  the  tip  of  the  ear.  The  grains 
should  be  closely  set  and  well  developed  thus  producing  a  firm  ear. 
Select  medium-sized  ears;  the  larger  the  diameter  of  the  cob  the 
greater  will  be  the  moisture  content  and  the  greater  the  difficulty  in 
thoroughly  drying  the  corn. 

Care  of  Seed  Com.  As  soon  as  husked  the  seed  corn  should  be  hung 
up  in  a  dry,  shady,  well  ventilated  place,  in  strings  of  10  to  15  ears  to 
insure  its  being  well  cured.  The  ears  can  be  rapidly  strung  by  looping 
coarse  twine  around  one  ear  above  another.  Hardly  any  place  is  too 
good  for  this  purpose,  for  well  preserved  seed  corn  means  many  dollars 
added  to  the  value  of  the  crop  the  following  year.  The  more  rapidly 
the  excess  moisture  can  be  removed  the  better  will  the  seed  germinate. 
Artificially  heated  rooms  are  therefore  the  best  place  for  drying  the 
seed  ears.    They  may  be  stored  in  a  cool,  dry  place. 

Test  the  Seed  for  Germinating  Power.  The  next  step  is  to  eliminate 
all  seed  ears  that  give  a  low  germination  test.  No  farmer  can  afford 
to  i > hint  seed  corn  without  knowing  whether  it  is  going  to  grow  or  not. 
'I'h is  should  not  be  done  until  the  seed  is  well  cured.  All  the  equip- 
ment thai   is  necessary  is  a  box  and  some  pieces  of  cloth.     Fill  the  box 


—  5  — 

to  within  an  inch  of  the  top  with  wet  sand  or  sawdust.  Level  the 
surface  and  spread  over  it  a  piece  of  cloth  that  has  been  marked  off 
into  checks  about  1-J  inches  square.  Number  the  checks  or  mark  one 
corner  so  it  will  be  possible  to  count  in  regular  order  to  any  particular 
check.  A  box  18  by  30  inches  is  large  enough  to  test  240  ears.  Lay  out 
the  ears  to  be  tested  in  a  row  where  they  will  not  be  disturbed  for  a 
few  days.  Starting  at  one  end  of  the  row  take  up  each  in  order  and 
with  a  small  knifeblade  pick  out  six  kernels  from  different  parts  of  the 
ear.  Place  these  on  a  check  in  the  germinator  corresponding  to  the 
number  of  the  ear  in  the  row  of  corn.  Cover  the  corn  in  the  germinator 
with  a  thick  cloth  and  set  the  box  in  a  warm  place  for  a  few  days.  If 
left  well  moistened  and  kept  warm  the  corn  will  germinate  in  5  or 
6  days.  Lift  the  cover  very  carefully  to  avoid  mixing  the  kernels  from 
different  ears.  (Or  simply  mark  off  the  checks  on  the  surface  of  the 
soil  and  plant  the  kernels  about  half  an  inch  deep,  firming  the  soil  over 
them.)  The  kernels  from  some  ears  may  not  germinate  at  all  and 
others  may  produce  weak,  sickly  sprouts.  Such  ears  cause  poor  stands 
of  corn  and  make  it  necessary  to  plant  more  seed  than  is  needed,  thus 
making  thinning  necessary.     All  such  ears  should  be  discarded. 

Grade  the  Seed.  The  final  step  in  selection  is  to  grade  the  seed. 
Partial  grading  is  accomplished  by  cutting  off  and  discarding  the  ends 
of  the  seed  ears  about  one  inch  from  the  tip  and  one-half  inch  from  the 
butt.  In  order  to  secure  a  perfect  stand  when  machinery  is  used  to 
do  the  planting,  it  is  necessary  to  have  the  kernels  of  uniform  size. 
Three  grades — large,  medium  and  small  are  sufficient.  By  shelling  each 
ear  separately  it  can  be  thrown  into  the  proper  grade  at  sight  without 
much  loss  of  time.  By  adjusting  the  planter  to  drop  the  same  number 
of  kernels  when  changing  from  one  grade  of  seed  to  another,  a  much 
more  even  stand  will  be  obtained  than  if  the  grading  had  not  been  done. 


—  6 


Fig.  3.     Selecting   seed   corn.      The   ears  shown   are  well   filled   and   are   placed   at  the 
best  height  on  the  plant. 


—  7  — 

Testing*  Individual  Plants. 

An  ordinary  field  of  corn  contains  many  distinct  strains,  some  of 
which  are  superior  in  yield,  vigor  and  plant  or  ear  characters  to  all 
others.  By  selecting  and  testing  superior  individual  plants  some  of 
these  choice  strains  can  be  isolated  and  later  increased  for  field  plant- 
ing. This  has  proved  a  very  effective  method  of  improving  the  corn 
crop. 

Ear-to-row  Test.  The  essential  feature  of  this  method  consists  in 
testing  each  ear  separately  in  a  row  by  itself.  The  rows  are  then 
compared  during  the  growing  season  and  as  regards  total  yield  and 
ear  characters.  Only  the  best  rows  are  selected  as  seed  for  the  increase 
plot.  Under  this  plan  the  test  plot  should  be  isolated  from  all  other 
corn  so  as  to  prevent  deterioration  by  crossing  with  poorer  strains. 

The  remnant  system  calls  for  an  ear-to-row  test  plot  as  the  first  step. 
Only  half  of  the  kernels  on  each  ear  are  planted  in  the  test  plot,  the 
remainder  being  held  over  until  the  following  year.  The  ear-to-row 
test  plot  need  not  be  isolated  under  this  plan  as  no  seed  is  saved  from  it. 
The  next  year  the  remnants  of  a  few,  usually  four,  of  the  highest 
yielding  ears  are  planted  in  an  isolated  breeding  plot,  and  the  stalks 
from  all  the  ears  planted  in  this  patch,  except  the  highest  yielding  ear, 
are  detasseled.  Seed  ears  are  selected  from  the  detasseled  rows  and 
grown  the  next  year  in  an  increase  field  to  supply  seed  for  general 
planting.  After  this  system  is  under  way  on  a  farm  there  is  main- 
tained each  year  a  small  isolated  breeding  plot,  an  increase  field  and 
an  ear-to-row  test  plot.  This  method  excludes  from  the  breeding  plot 
all  individuals  except  those  whose  producing  power  is  known  to  be 
high.  At  the  same  time  it  provides  for  the  intercrossing  of  these  most 
productive  strains  which  is  beneficial  in  corn.  By  continuing  the  tests 
from  year  to  year  the  work  will  tend  toward  the  selection  of  the  best 
producing  ears  for  all  or  average  seasons. 


